1. Field of the Invention
The present invention relates to a transportation device of a withdrawal circuit breaker, more particularly, to a withdrawal circuit breaker capable of preventing an incomplete separation of a main body of the circuit breaker and securing safety of a user by causing the left and right handle assemblies to be simultaneously operated when withdrawing the main body of the circuit breaker.
2. Description of the Conventional Art
In general, a circuit breaker is mounted on a distribution board which is provided for operation or control of power plants or substations, or for operation of motors, together with other electric appliances, and is used, in general, in a state that it is contained in a distribution box or a cradle fixed to the distribution board.
Within the distribution board, a base line of the circuit breaker and a load terminal are connected to a base line of a cradle and a load terminal to form a service position where voltage and current are provided and a test position where the base line of the circuit breaker and a load terminal are separated from the terminal of the cradle so that only a test of an operation of the circuit breaker may be available.
Here, an operation to put a circuit breaker in the distribution board to connect to the terminals of a cradle is called “draw in”, and an operation to put the circuit breaker out of the distribution board to separate the circuit breaker from the terminals of the cradle is called “draw out”. Further, the circuit breaker includes a control power plug which is configured to transmit an electric signal to the circuit breaker to turn on or turn off the circuit breaker at the service and test positions.
FIGS. 1 through 3 are views illustrating a main body of a circuit breaker in accordance with a conventional art accommodated within a distribution box (cradle). Here, FIG. 1 shows that the main body is in a test position in a state that a control power plug is not connected, FIG. 2 shows a state that the control power plug is connected, and FIG. 3 shows that the main body is in a service position. Here, the main body 2 is shown in a state that a front cover is removed.
The main body 2 is movably disposed within the distribution box 1. The test position is a position before the main body 2 is moved toward the distribution box 1. The main body 2 is moved to a service position after connecting a control power plug 3 with a control power connector 4 which are provided on an upper portion of the main body 2. Movement of the main body 2 is carried out by a transportation device 5 disposed at a lower part of the main body 2, and when the base terminal 6 and load terminal 7 of the main body 2 are connected with a terminal 1a disposed within the distribution board 1, movement of the main body 2 to a service position is completed, as shown in FIG. 3.
FIGS. 4 through 6 are views illustrating a main body and a transportation device of the circuit breaker according to a conventional art, in which FIG. 6 shows a state that a body plate 21 is removed.
The main body 2 is carried and moved by a transportation device 5. That is, a lead screw 11 is rotated by inserting a handle (not shown) into a handle hole 12 of a girder assembly 20 which is connected to a front surface of a truck 10, the truck 10 is moved so that the main body 2 is drawn in or drawn out. In this instance, the girder assembly 20 is fixed to the distribution box 1.
The handle assembly is located at left and right sides of a front portion of the transportation device 5. The handle assembly includes transportation device handles 25 and 26 and left and right sliding plates 22 and 23. The handle assemblies 22, 23; 25 and 26 are structured such that the left and right sliding plates 22 and 23 are coupled to the left and right handles 25 and 26, respectively, in an integrated body so as to be moved in the left and right directions within the girder assembly 20.
FIGS. 7A and 7B are views illustrating a moving position of the transportation device 5, in which FIG. 7A shows a state that parts of sliding plates 22 and 23 of the transportation device 5 are inserted into a rail hole 1b of the distribution box 1 in a restricted state, and a state that sliding plates 22 and 23 of the transportation device 5 are escaped from the rail hole 1b of the distribution box 1 in a released state, respectively.
In a case where it is intended to separate the main body 2 from the distribution box 1, the handles 25 and 26 of the girder assembly 20 have to be moved inside and the sliding plates 22 and 23 coupled to the handles 25 and 26 have to be escaped from the rail hole 1b. 
Meanwhile, in a case where only one of the sliding plates 22 or 23 is deviated from the rail hole 1b and another sliding plate is maintained in the sliding hole 1b due to a user's mal-operation, as shown in FIGS. 8 through 9B, the main body 2 can not be drawn out from the distribution box 1, thereby causing damages of parts and a safety accident to a user.